Category Archives: Uncategorized

July 1, 2022

Events – start of dry season in the southern ASEAN region – 2022

 

MEDIA RELEASE

START OF DRY SEASON IN THE SOUTHERN ASEAN REGION

 

Singapore, 1 July 2022 – The ASEAN Specialised Meteorological Centre (ASMC) has declared the start of the traditional dry season for the southern ASEAN region1. The dry season for the region is associated with the onset of the Southwest Monsoon and is likely to stretch into October 2022.

1 The prevailing La Niña conditions in the equatorial Pacific Ocean are forecast to continue weakening, with either La Niña or neutral conditions expected for the rest of the year. In addition, a negative Indian Ocean Dipole (IOD) is developing in the equatorial Indian Ocean and is expected to become established by August 2022. These two climate phenomena – La Niña and negative IOD, are expected to bring above-normal rainfall to most parts of the southern ASEAN region between July and October 2022.

2 Wet weather conditions in many parts of the southern ASEAN region during the first half of this year have helped to keep the fire hotspot and smoke haze situation generally subdued. In the coming months, although above-normal rainfall is forecast, there is still a risk of increased fire hotspot activity and smoke haze development during occasional periods of extended dry and warm weather.

3 Based on ASMC’s regional weather outlook, the overall smoke haze situation in the southern ASEAN region this year is not likely to be severe like that in 2015 and 2019, when there was prolonged drier-than-normal weather caused by a strong El Niño and a strong positive IOD respectively. Nonetheless, some transboundary haze may occur if the prevailing southeasterly to westerly winds blow smoke haze from persistent fires to neighbouring countries. Early preventive measures and vigilance are advised to mitigate land and forest fires during the dry season.

4 For regular and ad-hoc updates of the regional weather and smoke haze situation and early warnings, please visit the ASMC website at https://asmc.asean.org.

[1] The southern ASEAN region comprises of Brunei Darussalam, Indonesia, Malaysia, Singapore and southern Thailand.

May 10, 2022

Alert20220510 – Downgrade to Alert Level 1 for the Mekong Sub-Region

Downgrade to Alert Level 1 for the Mekong Sub-Region

In recent days, shower activities have increased over the Mekong sub-region. The showers have helped to improve the overall hotspot and haze situation, with localised hotspots and smoke haze observed over some parts of Myanmar, northern Thailand, and northern Lao PDR. With rainy weather forecast to continue in the coming days, the hotspot and haze situation over the Mekong sub-region is expected to improve further.

The hotspot count over the Mekong sub-region continued to be on a declining trend, with a total of 183 and 39 hotspots detected on 7 and 8 May 2022 respectively, from the surveillance by the NOAA-20 satellite.

April 29, 2022

Alert20220429 – Downgrade to Alert Level 2 for the Mekong Sub-Region

Downgrade to Alert Level 2 for the Mekong Sub-Region

In recent days, increased shower activities were observed over the Mekong sub-region which have helped to alleviate the overall hotspot and smoke haze situation there. Parts of Myanmar, northern Lao PDR and northern Thailand may still experience continued hotspot and smoke haze activity during dry periods. However the haze situation is expected to continue to improve with more rainy weather over the Mekong sub-region in the coming weeks.

A total of 2640 and 318 hotspots were detected in the Mekong sub-region on 27 and 28 April 2022 respectively from the NOAA-20 satellite.

December 10, 2021

 

MEDIA RELEASE

START OF DRY SEASON IN THE NORTHERN ASEAN REGION

Singapore, 9 December 2021 – The traditional dry season in the northern ASEAN region has started and is expected to extend into May 2022. The dry season usually sets-in following the Northeast Monsoon, which has become established over the ASEAN region in the past few weeks.

2          The equatorial Pacific Ocean is currently in a La Niña phase, which typically brings more rainfall to parts of the region. For the December 2021 to March 2022 period, near-to-above average rainfall is predicted for many parts of the northern ASEAN region, except for northern parts of Lao PDR, Myanmar and Viet Nam.

3          While this traditional dry season is predicted to experience near-to-above average rainfall over most of the region, fire hotspots and smoke haze could still develop during extended periods of dry and warm weather. During the Northeast Monsoon, the low-level winds in the region typically blow from the northeast or east. Transboundary haze may occur if the winds blow any smoke haze from fires to neighbouring countries. Early precautionary and mitigation measures are advised to prevent the occurrence of transboundary haze in the region.

4          For regular and ad-hoc updates of the regional weather and smoke haze situation and early warnings, please visit the ASMC website at https://asmc.asean.org.

[1] The northern ASEAN region comprises of Cambodia, Lao PDR, Myanmar, the Philippines, Thailand and Viet Nam.

July 16, 2021

 

MEDIA RELEASE

 

START OF DRY SEASON IN THE SOUTHERN ASEAN REGION

Singapore, 16 July 2021 – According to the ASEAN Specialised Meteorological Centre (ASMC), the traditional dry season in the southern ASEAN region[1] has started and is expected to extend into October 2021. The dry season is associated with the onset of the Southwest Monsoon in the region.

 

2          During this period, the equatorial Pacific Ocean is expected to remain in a neutral state, with no developing El Niño or La Niña.  However, in the equatorial eastern Indian Ocean, waters have been gradually warming and are forecast to become warmer than normal in the following weeks. This climate phenomenon, known as the negative phase of the Indian Ocean Dipole (IOD), typically brings more rainfall to the region. For the July to October period, above average rainfall can be expected over many parts of the southern ASEAN region.

 

3          Recent wet weather in many parts of the southern ASEAN region has helped to subdue the development of fire hotspots in the fire-prone areas. Despite the likelihood of higher than normal rainfall in the next few months, more fire hotspots could still develop during occasional extended periods of dry and warm weather. The prevailing southwest monsoon conditions mean that low-level winds in the region blow from the southeast or southwest, and occasionally from the west.  Transboundary haze may occur if the winds blow any smoke haze from fires to neighbouring countries.

 

4          ASMC assesses that the probability of a similar recurrence of the severe haze episodes in 2015 (El Niño year) and 2019 (positive IOD year) is low this year. Nonetheless, early precautionary and mitigation measures are advised to prevent the occurrence of transboundary haze in the region.

 

5          For regular and ad-hoc updates of the regional weather and smoke haze situation and early warnings, please visit the ASMC website at https://asmc.asean.org.

 

[1] The southern ASEAN region comprises of Brunei Darussalam, Indonesia, Malaysia, Singapore and southern Thailand.

February 25, 2020

Review of Regional Weather for January 2020

Review of Regional Weather for January 2020

Print Version

1. Overview

1.1 During January 2020, the region between 0° and 10°N predominately experienced below-average rainfall (Figure 1). For south of the equator, there was a mixture of below- and above-average rainfall, with the largest positive anomalies (wetter conditions) over southern Borneo. The rainfall anomalies over mainland Southeast Asia were small, which is expected given that January is the drier time of the year for that region.

era5_rainfall_anomalies
cmorph_bld_rainfall_anomalies
Figure 1: Rainfall anomalies for January 2020 based on ERA-5 reanalysis data (left) and CMORPH-Blended data (right). The climatological reference periods are 1981-2010 and 2001-2019 for ERA-5 and CMORPH-Blended data respectively. Green colour denotes above-average rainfall (wetter), while orange denotes below-average rainfall (drier).


1.2 Overall, most of Southeast Asia experienced above-average temperature during January 2020 (Figure 2). The largest anomalies occurred over northern Thailand, Laos and Viet Nam. Only western and northern Myanmar, and some parts of Cambodia, experienced near-average temperatures.

era5_temperature_anomalies

Figure 2: Temperature anomalies for the month of January 2020 based on ERA-5 reanalysis. The climatological reference period is 1981-2010. Red colour denotes above-average temperature (warmer), while blue denotes below-average temperature (colder).


2. Climate Drivers

2.1 A Madden–Julian Oscillation (MJO) signal developed over the Maritime Continent (Phase 4) during the first week of January 2020 (Figure 3). The signal strengthened rapidly, and then propagated eastwards with the main precipitation envelope reaching the Western Pacific (Phase 7). By the end of January, however, this MJO signal had weakened and became indiscernible. Phase 4 normally brings wetter conditions for much of Southeast Asia, while Phase 7 is associated with drier conditions. Phases 5 and 6 bring a mixture of wetter and drier conditions.

mjo_phase_diagram

Figure 3: The MJO phase diagram. The diagram illustrates the movement of the MJO through different phases, which correspond to different locations along the equator (denoted in the text). The distance of the index from the centre of the diagram is related to the strength of the MJO. Values within the grey circle are considered weak or indiscernible (data from the Bureau of Meteorology, Australia).


2.2 The strong positive Indian Ocean Dipole (IOD) event from 2019, which had been weakening since November 2019, continued to weaken and returned to the neutral state in January 2020. The IOD typically remains in the neutral phase during the season from January to April.

September 12, 2019

test

July 12, 2019

Outlook for Land Fires and Smoke Haze Situation (16 – 31 July 2019)

Outlook for Land Fires and Smoke Haze Situation (16 – 31 July 2019)

Issued 12 July 2019

The northern ASEAN region is currently in its traditional rainy season which will prevail for the next few months. With wet conditions predicted for the northern ASEAN region in the second fortnight of July 2019, hotspot activities there are expected to be generally subdued. In the southern ASEAN region, drier-than-usual conditions are expected during the outlook period. This could contribute to an increase in hotspot activities in the fire-prone provinces of Sumatra and Kalimantan, and increase the risk of occurrence of transboundary haze in the region.

March 7, 2019

ASMC Bulletin (Issue #3, Mar 2019)

ASMC Bulletin (Issue #3, Mar 2019)

February 28, 2019

Outlook for Land Fires and Smoke Haze Situation (1 – 15 Mar 2019)

Outlook for Land Fires and Smoke Haze Situation (1 – 15 Mar 2019)

Issued 28 February 2019

With warm and dry weather prevailing over many parts of the Mekong sub-region, current hotspot activities and smoke haze situation are expected to persist. In the southern ASEAN region, hotspot activities are likely to remain subdued except for some isolated hotspots with localised smoke plumes that may emerge during brief periods of dry weather.